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The purpose of this paper is to show some techniques to perform line contingency screening efficiently.

Computation efficiency and speed are mandatory requirements of contingency screening, especially when multiple outages need to be considered. The classical bounding principle, i.e. the idea that the effects of an outage are restricted to the area where the outage occurs, becomes increasingly difficult to apply to multiple contingencies. In the present work a comprehensive strategy, based on a systematic elimination of non-dangerous outages, is shown to be easily applicable to both single and double contingencies.

Tests show the efficiency of the proposed methods with reference to test systems and to an actual network with up to 800 buses.

The bounding approach is the basis of most efficient contingency screening methods based on the linear dc load flow model. In the present work the method is re-considered to improve computational efficiency. The symmetry of the dc Jacobian and the sparse inverse technique are suitably exploited in the evaluation of line outage distribution factors; this also allows a combination of single and double line contingency screening into a single procedure.

The purpose of this work is that of providing the guidelines of an efficient implementation of power flow computations using the MATLAB computation environment.

The goal of obtaining high efficiency from MATLAB programs often proves elusive unless special care is taken in exploiting the vectorising capability of MATLAB programming. In the present paper the implementation of Newton‐Raphson power flow in MATLAB is examined with particular emphasis on the way of obtaining a vectorisable code capable of achieving effective numerical performance by exploiting its formulation in terms of complex variables.

Tests on actual networks with up to 1,300 buses are presented. They show that the complex power flow is as efficient as the best implementations of the Newton Raphson power flow using real variables, as long as the operations involved are reordered with the aim of exploiting the vectorisation capabilities of the MATLAB environment.

It is shown that improved numerical efficiency in the MATLAB can be obtained through its formulation in terms of complex variables. The complex Newton‐Raphson load flow, not very common in practical uses, is shown to have many desirable qualities from the point of view of MATLAB programming and is presented in detail.

The purpose of this work is that of showing some efficient techniques to perform PV-PQ node type switching in multiple power flow computations.

Reactive generation limits of generation buses must be taken into account to obtain realistic power flow solutions. This may result computationally demanding when many power flow computations are required as in contingency screening or Monte Carlo simulations. In the present paper, the implementation of efficient PV-PQ node type switching is examined with particular emphasis on the efficiency of computation. Some different methods are proposed and compared on the basis of computation speed and accuracy.

Tests show the efficiency of the proposed methods with reference to actual networks with up to 800 buses.

The classical method of (partial) re-factorisation is not very efficient when many power flow solutions are to be evaluated. In the present work, a different approach is proposed; it is based on grounding each PV node by a fictitious short-circuit branch which is removed when the node type is changed to PQ. This operation is carried out by compensation of the solution and combined with the modifications required for contingency simulation.

Discusses collection building of contemporary German belles‐lettres and introduces 20 contemporary German‐language writers of the younger generation, presenting their bio‐bibliographies. Librarians who are not already collecting these authors might consider expanding their German literature collections by adding some of the works listed.

This chapter compares programmes for urban housing regeneration in France and England, showing how ideological similarities reflected in policy ideas and programmes played out differently in significantly different contexts.

The chapter draws on results of several major research programmes, including in-depth extensive fieldwork in a number of cities and regions in France and England. Field research included participant observation in participatory planning events, interviews, home visits, guided walks in the districts, etc. These enabled a multi-site and multi-perspective understanding of urban housing renewal at different sites.

In both contexts, early promises for participation in housing renewal gave way to an imperative for demolition, justified on purely technical grounds that were not shared with participants. The linking of social mix and demolition for local ‘improvement’ also then appeared to be a contradiction between different policies that few residents could endorse, other than selected beneficiaries. Participation, social mix and demolition thus formed an unholy trinity in urban renewal policies.

Housing renewal requires much greater commitment to the experience of residents, to avoid exacerbating social problems rather than relieving them.

The chapter reflects on a wealth of in-depth research over more than a decade to consider the broader implications and outcomes of housing renewal programmes in two countries. It highlights the different balances of power in the two cases and the trajectories of respective urban social politics, including the overlaps between policy objectives and similarities in the government of housing renewal. It also highlights the determination and commitment among residents to the value of housing that is judged from the outside to be ‘poor’.

In some settings, sharecropping is associated with large extended families, high fertility, and early age of marriage. These demographic practices are often considered to be labor strategies for working extensive share‐tenancies. Where agricultural production is primarily labor intensive, landlords can increase their income, within certain limits, by maximizing the number of adult workers. If landlords hold considerable power over their tenants, they may have a large influence on demographic practices. Although this relationship between sharecropping and some of these demographic practices is found throughout much of history in northern Italy, the evidence is less clear for fifteenth‐century Tuscany. Herlihy and Klapisch‐ Zuber's study of the Catasto of 1427, a set of tax declarations, found no relation between household structure and land tenure. Some of their work suggested that fertility was higher among sharecroppers, but this relationship was not specified in detail. They did not consider the relationship between land tenure and age of marriage. This paper reconsiders the relationship between land tenure, household structure, fertility, and age of marriage. To try to correct for problems with Herlihy and Klapisch‐Zuber's land tenure variable, their data were aggregated to the administrative unit of analysis. The aggregated data show that sharecropping in rural Tuscany in 1427 was associated with household extension, high fertility, and early age of marriage, although the magnitude of this relationship was not large. Possible reasons for this weak relationship are discussed.